1. Field of the Invention
The present invention relates to a compound bow, and more particularly to a compound bow in which a cable connected between an upper wing and a lower wing is removed, and the distortion of a cam is prevented, thereby facilitating maintenance and ease of replacement of parts of the bow.
2. Description of the Prior Art
As generally known in the art, a compound bow is one generally used for hunting which, upon pulling, is easily drawn using a roller type cam or wheel without applying a large force, and upon shooting, increases a shooting force about two times to thereby speed up an arrow with great force.
FIG. 14 is a perspective view of a compound bow according to the prior art, FIG. 15 is a bottom view of a compound bow according to the prior art, and FIG. 16 is a partial enlarged perspective view of a prior compound bow in which a cam thereof is in a distorted state.
As shown in FIGS. 14 to 16, the compound bow includes a handle 10 made of an aluminum material, on both ends of which an upper wing 20 is coupled to the upper end thereof and a lower wing 26 is coupled to the lower end thereof. The upper and lower wings 20 and 28 are provided, at each end 22 and 28, with cut-outs 21 and 27, respectively, in which a cam is rotatably installed by means of an eccentric shaft 70.
The cam consists of an upper cam 30 and a lower cam 36, first and second cables 40 and 46 are respectively connected between the upper cam 30 and the end 28 of the lower wing 26, and the lower cam 36 and the end 22 of the upper wing 20, and a bow string 50 is connected between the upper and lower cams 30 and 36. Here, the first and second cables cross each other in X type.
A cable guide 60 is horizontally installed at one side of the middle portion of the handle 10, the cable guide has a glider 66 movable along the cable guide, and the bow string 50 is inserted in the glider 66.
The glider 66 serves to pull the first and second cables 40 and 46 in one direction. If the first and second cables 40 and 46 are not pulled in one direction, upon shooting an arrow, the arrow and the fletching thereof collide with the first and second cables 40 because the first and second cables 40 and 46 are aligned with the bow string 50.
In the prior compound bow constructed as above, when the bow string 50 is pulled, the upper and lower cams 30 and 36, each having eccentric shafts 70, rotate to wind and draw the first and second cables 40 and 46. At the same time, the upper and lower wings 20 and 26 are curved so that the glider 66 is moved in an end direction of the cable guide 60. Here, the upper and lower cams 30 and 36 come to be distorted.
That is, as shown in FIG. 16, the upper cam 30 is coupled to the end 22 of the upper wing 20 with the eccentric shaft 70, the bow string 50 is coupled at its one end to a large-diameter groove 31 of the upper cam 30, and the first cable 40 is connected between a small-diameter groove 32 of the upper cam 30 and the end 28 of the lower wing 26. In addition, the lower cam 36 is coupled to the end 28 of the lower wing 26 with the eccentric shaft 70, the bow string 50 is coupled at the other end thereof to a large-diameter groove 37 of the lower cam 36, and the second cable 46 is connected between a small-diameter groove 38 of the lower cam 36 and the end 22 of the upper wing 20.
Thus, when the bow string 50 is pulled, the upper and lower cams 30 and 36 rotate about each eccentric shaft 70. Herein, when an arrow is shot after the bow string is pulled to a position where the largest-diameter portions of the cams pass over the respective vertical states about the eccentric shafts 70, the arrow is shot with great force generated due to strong elasticity of the string instantly returning to its original position.
However, in such a compound bow, upon shooting the bow, the first and second cables 40 and 46 and the bow string 50 are in the line, so that the first and second cables 40 and 46 are supported in force in one direction by the cable guide 60 in order to prevent an arrow and the feathers thereof from coming into contact with the first and second cables 40 and 46. Thus, as shown in dotted line in FIG. 16, the upper and lower cams 30 and 36 are distorted about the eccentric shafts 70, so that the ends 22 and 28 of the upper and lower wings 20 and 26 are apt to be deformed, and that, when the bow string 50 is pulled and then released, due to a force of the upper and lower cam 30 and 36 restoring to an original position from a distorted state, the lifetime of the upper and lower wings 20 and 26 becomes shortened, and a trembling effect occurs and the accuracy of the arrow deteriorates.
In order to connect the first and second cables 40 and 46 of the compound bow with the bow string 50, as set forth before, the first and second cables 40 and 46 each are connected between the upper cam 30 and the end 28 of the lower wing 26, and between the lower cam 36 and the end 22 of the upper wing 20, and the bow string then is connected between the upper and lower cams 30 and 36. On the contrary, in the case of maintenance and replacement of the first and second cables 40 and 46 and the bow string 50, the first and second cables 40 and 46, each having been connected between the upper cam 30 and the end of the lower wing 26, and between the lower cam 36 and the end of the upper wing 20, are disconnected in order, the bow string 50, which has been connected between the upper and lower cams 30 and 36, is disconnected, and then the maintenance and replacement are carried out. In order for the connection and/or the disconnection of the first and second cables 40 and 46 and the bow string 50, a special tool, a pool bow press, having the size about two times the compound bow, should be used. However, in the case where the compound bow is used is a plain and the first and second cables 40 and 46, or the bow string 50 should be repaired or replaced, problems arise in that it is impossible to repair or replace the first and second cables 40 and 46, and the bow string 50 without the pool bow press, and that if one carried the pool bow press with him, he is restricted in movement in using the compound bow.